The Dockers are through to the RUR Charity Cup semi-final after an entertaining game at Division One Oakwood.
The hosts took an early lead through Nick Sullivan, but Newhaven hit straight back as Lee Robinson turned in Ryan Blunt’s low cross.
Bailie Rogers’ firm header from a Callum Edwards corner gave the visitors a 28th lead, before Luke Donaldson struck in first half stoppage time to extend the lead to two.
Newhaven spurned a number of opportunities in the second half to kill the game off and had to see out a nervy last ten minutes when Sullivan halved the home side’s deficit.
But the remaining time was dealt with by Newhaven, who will now travel to Eastbourne United in the semi-final in January.